Arrangement for transporting articles along a closed path defined by a guide

Abstract: The arrangement disclosed comprises at least one transport module (1) moved along two parallel rails (5,6) defining a closed path and running on them with rolling friction through articulated trolleys (3) pivotally mounted on the structure of the module and each comprising a pair of antifriction bearings (13) inclined so as to touch the respective rail in two points spaced 90° in the cross-section plane of the rail.

Description: The present invention relates to an arrangement for transporting articles along a closed path comprising a guide defining the path, at least one transport module movable with rolling friction on the guide and means for dragging the module along the path. Arrangements of the above-mentioned type are employed in several fields. In the field of industrial automation, e.g., they are used as collecting/sorting systems in assembly lines, while in postal automation they are used for the sorting and forwarding of bulky letter, packages and the like. U.S.Patent N° 4,310,276 discloses a machine for transporting objects from a leading station to a sorting station, wherein the objects are loaded on mobile carriages slidable along a monorail guide each through a pully rolling on the upper surface of the rail and a pair of rollers which slidably engage with the opposite sides of the lower portion of the guide. This machine and other similar in the art have the drawback that along curved portions of the path sliding friction is generated between the rail and parts rolling on it which, besides reducing the speed, causes vibrations and unbalances that make the module noisy and, in addition, can cause derailment of the module with consequences easy to conceive. Moreover, such devices are unstable in the sense that, being not constrained enough to the rail, entail limitation in speed and in the transversal inclination of the guide. The general object of the present invention is to overcome the drawbacks of the prior art and provide an arrangement for transporting articles along a closed path defined by a guide which features low noisiness, high transportation speed, short replacement time and, moreover, is inexpensive. Another object of the present invention is to provide a transport module for closed path defined by a guide which is stable, i.e. capable of operating with any transverse inclination of the guide without limiting the velocity of the module and, moreover, is balanced and does not cause vibrations. These and other objects of the invention, which will become more apparent hereinafter, are achieved, in accordance with the present invention, by an arrangement for transporting articles along a closed path, of the type comprising at least one transport module movable with rolling friction along a guide defining the path, the arrangement being characterized in that the guide consists in at least two parallel tubular rails, that the module is slidably engaged with each of the rails through articulated trolleys distributed in such a way that at least one rail is engaged with at least two articulated trolleys, each trolley being rotatable about an axis perpendicular to the respective rails and abutting on it through at least two antifriction bearings tangent thereto in at least one pair of points distant 90 degrees each from the other in the plane of the rail cross-section, each trolley being articulately fixed to the structure of the module through a sintered self-lubricating bush. Thanks to this solution the following advantages are obtained: high speed, low central forces in curvilinear sections, absence of unbalancings, absence of vibrations, very low noisiness, low costs. Further characteristics and advantages of the invention will result better from the detailed description of a preferred, but not exclusive, embodiment of an arrangement for transporting articles along a closed path defined by a guide, taken in conjunction with the accompanying drawings attached merely by way and not limiting example, wherein: Fig. 1 illustrates schematically in a perspective view the arrangement in accordance with the present invention; Fig. 2 shows a constrained transport module used in the arrangement of Fig. 1 along with portion of rail guide; Fig. 3 shows in greater detail the module of Fig. 2 in a cross-sectional view; Fig. 4 shows an enlarged detail of Fig. 3; and Fig. 5 illustrates schematically an articulated trolley mounted on the module of Figs. 2 and 3, along with the respective rail, in a cross-sectional view. With reference to the figures, the arrangement for transporting articles along a closed path defined by a guide comprises at least a transport module 1, movable with rolling friction on the guide formed by two rails 5,6 extending along the closed path and parallelly disposed in vertical planes in the embodiment shown in the figure, but not necessarily. Each rail has a circular cross-section and is formed by a number of portions joined together. The module 1 is dragged along the path by a flexible dragging member 7 such as a chain, a belt or a rope. In the embodiment shown in Fig. 1, such member 7 is a chain driven by a motor through a sprocket wheel 8. The transport module 1 comprises a C-shaped plate-like structure 2 (see Figs. 2 and 3), extending transversely of the rails 5,6 so that they run between the bent ends 2a, 2b; mounted on these bent ends are articulated trolleys 3 which extend inwards and abut on the corresponding rail 5,6 while the unbent portion 2 is provided with holes 10 for fixing the support (not shown) carrying the articles and with a pi-section bracket 4 for anchoring the chain 7. One of the bent ends (2b in Fig. 3) consists of an unequal angle bracket, one side of which mounting the respective articulated trolley(s) 3 and the other side being adjustably fixed to structure 2 through two screws 18 (only one visible in the figure) and two guide pins 20. A micrometer adjusting screw 16 allows the adjusting of the position of bracket 2b and therefore the optimization of the position of the respective articulated trolley(s) 3 on the respective rail 5. In the embodiment illustrated in the figures there are represented four trolleys, two mounted on the upper bent end and two in the lower one, but their number can be changed provided that the stability of the module is assured in the sense that it is prevented from rotating both about an horizontal axis and about a vertical axis. In Fig. 5 there is illustrated schematically an articulated trolley along with the respective rail (6 in Fig. 5), a respective bush 14 and a respective clamping plate 15. Each trolley 3 is composed of a substantially cylindrical body 11 having an axis y-y perpendicular to the respective rail, mounting two ball-bearings 13 through respective bearing pins 12 each making an angle of 45 degrees with axis y-y, so that the bearings 13 touch the respective rail at two points symmetrical with respect to axis y-y and at angular distance of 90 degrees in the plane of the rail cross-section (see Fig. 5). The upper portion of the body 11 terminates coaxially with a hub 11a surrounded by a respective sintered self-lubricating bush 14 that allows the automatic rotation of the trolley on the curved portions of the rail adapting it thereto. Bush 14 is fixed to the respective bent end 2a, 2b of plate 2 (see Fig. 4). The hub 11a is inserted in the respective bush and projects about 0.5 mm. above the surface of the respective bent end. A clamping plate 15 is fixed to the hub through a screw 19 and its function is to prevent the trolley from slipping off before mounting the module on the rails. The module is connected with and removed from the guide rails by suitably unloosing and tightening the screws 16,18 (see Fig. 3). Once the module has been connected with the rails and its position is adjusted through the screw 16, the bracket 4 is connected to the chain 7 through a pin 17 and then the support for the articles is fixed to the structure 2 through holes 10. The operation of the transport device is evident to those skilled in the art and therefore is not described in detail herein. Thus the invention fully achieves all the above-mentioned objects. In fact, the arrangement for transporting articles along a closed path defined by a guide, in accordance with the present invention, allows the elimination of the sliding friction on the rails at curved portions thereof through the use of the articulated trolleys and axis/wheel sliding friction through the use of antifriction bearings whereby it features a high transport speed, absence of vibrations and very low noiseness. Moreover the transport module of the present invention features absence of unbalancings because of compensation of all involved forces and it results to be very stable being slidably constrained at at least three points, whereby it does not oscillate and can operate with any transversal inclination of the rails. The module of the present invention further features low centrifugal forces in the curved sections of the path because of low centrifugal accelerations that such a system is capable of establishing. Naturally several modifications and variants can be conceived which, being evident to those skilled in the art, fall within the sphere of the inventive concept. For instance, the plate-like structure could be thought as disposed inside the path with bent ends 2a, 2b pointing outwards, or the structure could have a height smaller than the gauge with trolleys abutting on the rails from the inside (instead of from outside as shown in Fig. 3), the bearings can be roller bearings instead of ball-bearing and so on. Lastly, materials and dimension can be varied according to production and use needs and circumstances, while complying with the characteristics illustrated, described and claimed below.

Claims: Arrangement for transporting articles along a closed path of the type comprising a guide defining said path, at least one transport module (1) movable with roller friction on said guide, and means (4, 7, 8, 9, 17) for dragging said module along said path, characterized in that said guide is composed of at least two parallel tubular rails (5, 6) and said at least one module is slidably engaged with each of the rails through articulated trolleys (3) distributed in such a way that at least one rail is engaged with at least two articulated trolleys, each trolley being rotatable about an axis (y-y) perpendicular to the respective rail (6) and abuts on it through at least two antifriction bearings (13) touching it at at least a pair of points, each point being at an angular distance of 90° in the plane of the rail cross-section. Arrangement according to claim 1, characterized in that said dragging means comprise a flexible driving member (9) anchored to said at least one module (1) and extending parallelly to said rails, and a motor (9) for moving said driving member. Arrangement according to claim 2, characterized in that said driving member (7) is a chain. Arrangement according to claim 1, characterized in that each of said articulated trolleys (3) comprises: a substantially cylindrical body (11) having an axis (y-y) perpendicular to the respective rail and terminating coaxially at one end with a hub (11a) insertable in a sintered self-lubricating bush (14) rigidly fixed to the structure of said module, and at least one pair of antifriction bearings (13) mounted on pins rigidly fixed into said cylindrical body (11) and each making an angle of 45° with said axis (y-y). Constrained module (1) for transporting objects on a closed path, moved with rolling friction by dragging means (4, 7, 8, 9, 17) on a pair of parallel rails (5, 6) having tubular cross-section and defining said closed path, said module comprising: a plate-like structure (2) parallel to the strip delimited by the rails and extending transversely thereof and supporting the container for the transported objects, said plate-like structure having its ends (2a, 2b) bent perpendicularly to said strip, and at least three articulated trolleys (3) pivoted on said bent ends, alternately distributed thereon and extending inwards to abut on the respective rail and each touching it at two points located at an angular distance of 90° in the plane of the rail cross-section. Constrained transport module for closed path according to claim 5, characterized in that each of said articulated trolleys comprises: a substantially cylindrical body (11) having an axis (y-y) perpendicular to the respective rail and terminating coaxially at one end with a hub (11a) inserted in a sintered self-lubricating bush (14) rigidly fixed on the respective bent portion of said plate-like structure, and at least one pair of antifriction bearings (13) mounted on pins rigidly fixed into said cylindrical body (11) and each making an angle of 45° with said axis. Module according to claims 5 and 6, characterized in that at least one of said bent ends is composed by an unequal angle bracket (26) adjustably connected to said plate-like structure through an adjusting screw (16) and a plurality of securing screws (18). Arrangement for transporting articles according to claims 1 to 4, characterized in that said parallel rails (5, 6) individuate vertical planes. Arrangement for transporting articles along a closed path defined by a guide, as hereinbefore described and illustrated for the proposed objects.

Inventors: REALI LANFRANCO, REALI, LANFRANCO
Applicants: ALSTHOM CGE ALCATEL, ALCATEL
Application year: 1994
Main classification: B65G17
IPC codes: B65G21, B65G17